1. Field of the Invention
This invention relates generally to grinding polishing or surfacing machines and more particularly to a head assembly used for retaining abrasive pads.
2. Description of the Related Art
Various scraping, grinding, and sand blasting machines have been designed over the years to resurface floors necessitated due to wear and damage to floor surfaces over long periods of repeated and continuous use. For example, painted concrete floors are often resurfaced after the existing paint becomes chipped and the floor surface becomes pitted. Carpeting, linoleum tiles, and other floor coverings are often originally secured to the floor using an adhesive to prevent movement, but these floor coverings become worn, loose, or cracked over time. When these floor coverings are taken for replacement such as by using hand scrapers and other tools, the exposed floor surface with remaining floor covering and hardened adhesive is typically very rough. Before applying a new covering to the floor such as by repainting, applying linoleum tile, carpeting, or the like, it is usually required that any remaining paint, linoleum, carpet padding, or hardened adhesive of the previous floor covering be removed by resurfacing the floor.
One type of resurfacing machine often used to resurface floors is a small, hand-held grinding machine which utilizes grinding pads. The grinding machine is moved along the floor surface by an operator from a kneeling position on the floor surface. While these grinding machines are convenient to transport to the site where the floor to be resurfaced is located, they cover only a small surface area with each pass along the floor surface and thus require considerable time to grind or sand even small areas of the floor.
Larger wheeled resurfacing machines have thus been developed which utilize larger grinding pads or cutting blades to resurface larger areas of the floor more efficiently and expediently. Such resurfacing machines typically have a wheeled chassis supporting a motor which drives a rotary floor grinding mechanism and resurfacing disk. An upstanding push handle extends from the chassis to allow the operator to stand during operation rather than kneel. Thus, these resurfacing machines cover a much larger floor area with each pass and are easier to operate than the hand-held grinding machines.
While the larger wheeled resurfacing machines are easier to operate and cover more surface area per pass than the hand-held grinders, current machines cannot operate at higher speeds. Current abrasive pad mounting designs tend to fail when the rotation rate of the grinder head is increased. Moreover, current abrasive pad designs tend to shear off from current grinder head designs when rotation speed is increased.
It is an object of this invention to provide a grinder head assembly for a resurfacing machine capable of withstanding 500 rotations per minute (RPM) and most preferably an order of magnitude greater. Moreover it is an object of the current invention to provide a grinder head capable of operating at such speeds and capable of keeping the abrasive pressure substantially consistent on the areas of greater relief than prior devices.